Fuel injection is performed in a precombustion chamber of a gas engine in accordance with an operation of a check valve for injecting fuel.
In this case, types of the check valve for injecting fuel include a ball type, a plate type, and a poppet type. These types of the check valve for injecting fuel are selectively applied according to conditions due to their advantages or disadvantages.
Combustion of fuel having a heavy mixed concentration in which air and fuel are mixed with each other near a theoretical air-fuel ratio, is performed so that carbon can be generated.
In this case, since carbon is fixed to the check valve for injecting fuel, opening/closing of the check valve is not smoothly performed, or opening/closing of the check valve itself is not performed.
For this reason, a poppet type check valve that is known to have a comparatively strong tolerance with respect to carbon, is mainly used in the gas engine.
In this case, the check valve used in the gas engine may be maintained at an appropriate durability to be driven in a high-temperature and high-pressure environment.
Meanwhile, a poppet type check valve 100′ according to the related art will now be described in detail.
As illustrated in FIGS. 1 and 2, the poppet type check valve 100′ according to the related art is combined with a prechamber 300 with a thread 116 formed at an upper end of a body 110′.
In this case, since a check valve mounting portion in which a lower end of the body 110′ of the check valve 100′ and the prechamber 300 contact each other, is sealed with a coupling force generated by thread engagement, high-temperature, uncombusted fuel can be prevented from flowing backward, as illustrated in FIG. 2.
However, since the check valve mounting portion is narrow, even when the check valve 100′ is installed to be slightly twisted, a gap is formed in a check valve seat portion in which the body 110′ of the check valve 100′ and a circumference of a lower end of a spindle 120′ contact each other, such that uncombusted fuel may flow backward through the gap.
In the poppet type check valve 100′ according to the related art, carbon generated in uncombusted fuel may be fixed to the spindle 120′ in accordance with flow of uncombusted fuel.
Also, in the poppet type check valve 100′ according to the related art, the body 110′ and the spindle 120′ are combined with each other using several parts so that it takes a long time to perform disassembly and assembly and thus productivity of the poppet type check valve 100′ is lowered.
In the poppet type check valve 100′ according to the related art, since the spindle 120′ is eccentrically lowered and slantly comes into contact with the body 110′, a one-sided abrasion phenomenon in which abrasion is concentrated on a guide portion between the spindle 120′ and the body 110′ and the check valve seat portion, occurs, and thus durability of the poppet type check valve 100′ is lowered.